1. Field of the Invention.
The invention in general relates to line pressure probes that are used in line leak detector systems, and more particularly with such a pressure probe which is able to provide a pressure signal that is more reliable representative of a line leak and more compact than prior art pressure probes.
2. Description of the Prior Art.
Line pressure probes have been widely used in the petroleum industry for many years. The line pressure probes generally report on the line pressure to a central monitor which utilizes the pressure data to provide warning of line leaks and to shut down pumps on lines that are leaking. Such pressure probes have become an essential part of hydrocarbon storage and dispensing facilities since even very small leaks can result in the loss of thousands of dollars of hydrocarbon, and because spills from leaks have become highly regulated and expenses of cleanup can be enormous.
Up to now most line pressure probes have consisted of line pressure switches which provide a signal if line pressure falls below a certain value, for example, 5 psi. These probes are susceptible to providing an erroneous leak indication when the pressure drop is due to temperature contraction. More recently line pressure probes which provide a continuous pressure reading and also provide the ground temperature have been available. Such probes allow the central monitor to analyze the pressure and temperature data to provide a more reliable indication of whether a leak has occurred. However, these prior art systems are all bulky, requiring spatial dimensions of the order of a foot or more. Moreover, they have generally included relatively thin parts, such as temperature probe extensions and mechanical levers connecting the probe to conduits and tanks. Since the areas in which the probes are used are often in relatively cramped underground locations or in locations where machines are commonly operated, it would be useful to have a compact probe with no extending parts.